What setup to do outreach with PST?

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Stephanh
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What setup to do outreach with PST?

Post by Stephanh » Thu May 11, 2017 1:12 am

Hi,

Newbie alert!! So go gentle on acronyms and specialized vocabulary. :D

I purchased a PST and would like to do some outreach. My goal is to use the laptop to show the live image of the sun at local schools science fairs.
I already have a good tripod, a ZWO ASI120MM camera and laptop with the needed cables.

Will that set-up work? I have read that it might be difficult to reach focus with the PST...

Would using live-view on a DSLR a better bet? I'd rather stay away from the eyepiece viewing as it limits access to one children at a time.

thanks!

Stephan

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Merlin66
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Re: What setup to do outreach with PST?

Post by Merlin66 » Fri May 12, 2017 5:29 am

Stephan,
You can quickly double check that the ASI 120 will focus on the PST by just trying it!

There's very limited back focus available on the PST (it was designed as a visual instrument).
If you experience issues try adding a x2 barlow lens to the front of the nosepiece this might just get the you the required spacing.
The situation is worse with the DSLR and you will definitely need a barlow lens upfront.
Hope this helps.
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Re: What setup to do outreach with PST?

Post by Stephanh » Sat May 13, 2017 2:32 am

The PST purchase felt thru. I now am looking at a modified PST from a local user . It is installed on a 90mm achromat with a 1000mm focal length. It comes with an ERF and a BF10 for diagonal.
The ASI120MM will not give me full disk view with this setup. Not even with a .5 reducer.
I have a 50mm guide scope (175mm focal length) that would give me full disk with that camera. The question is: will I need an ERF on the 50mm scope to block the heat and UV? Or would I need to reduce the aperture?
Any help would be greatly appreciated !
Thanks!!

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Merlin66
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Re: What setup to do outreach with PST?

Post by Merlin66 » Sat May 13, 2017 2:37 am

Stephan,
You'll need some protection on the 50mm finder.
I'd recommend a Baader solar film filter - you can then show the equivalent view of the sun in white light.
"Astronomical Spectroscopy - The Final Frontier" - to boldly go where few amateurs have gone before
https://groups.yahoo.com/neo/groups/ast ... scopy/info
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer

Stephanh
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Re: What setup to do outreach with PST?

Post by Stephanh » Sat May 13, 2017 2:43 am

Thanks for the quick reply.

Is this the commonly used filter with which you can only see the sun spot on a totally white disk? I was hoping to have a more "Ha view" since I will be using the back end of a PST and blocking filter.

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Merlin66
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Re: What setup to do outreach with PST?

Post by Merlin66 » Sat May 13, 2017 3:02 am

Stephan,
The PST mod won't fit a 50mm finder....
It needs to be positioned 200mm inside prime focus of an f10 telescope.
"Astronomical Spectroscopy - The Final Frontier" - to boldly go where few amateurs have gone before
https://groups.yahoo.com/neo/groups/ast ... scopy/info
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer

Stephanh
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Re: What setup to do outreach with PST?

Post by Stephanh » Sat May 13, 2017 3:31 am

Oh I see.
What would be a solution to get the full disk in HA with this PST mod arrangement while keeping the same camera? I guess using a reducer is out of the question.

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Merlin66
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Re: What setup to do outreach with PST?

Post by Merlin66 » Sat May 13, 2017 3:45 am

Stephan,
Not easy!!
You could try a reducer before the diagonal.
"Astronomical Spectroscopy - The Final Frontier" - to boldly go where few amateurs have gone before
https://groups.yahoo.com/neo/groups/ast ... scopy/info
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer

Stephanh
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Re: What setup to do outreach with PST?

Post by Stephanh » Sat May 13, 2017 5:38 am

But this reducer would bring the f-ratio down, from f10 to....f5 for a 0.5X. Correct? Wouldn't that go against the f10 requirement? Getting confused....

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Re: What setup to do outreach with PST?

Post by Merlin66 » Sat May 13, 2017 8:19 am

Stephan,
The reducer should be placed between etalon and the camera....
The etalon will still see the f10 entrance beam....
"Astronomical Spectroscopy - The Final Frontier" - to boldly go where few amateurs have gone before
https://groups.yahoo.com/neo/groups/ast ... scopy/info
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer

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Re: What setup to do outreach with PST?

Post by marktownley » Sat May 13, 2017 9:14 am

The sun is really blank at the moment, so other than a few proms theres not much to see. I think you will get more of a wow factor getting people to look through the scope.
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Montana
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Re: What setup to do outreach with PST?

Post by Montana » Sat May 13, 2017 5:42 pm

There is a double stack PST for sale in the sales section of this site

Alexandra

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